Many formulations such as inks, paints, mill-bases and plastics materials require effective dispersants for uniformly distributing a particulate solid in a non-polar organic medium.
Numerous publications disclose polyester amine dispersants derived from a poly(C2-4-alkylene imine) such as polyethylene imine to which is attached a polyester chain. The polyester chain may be derived from 12-hydroxy stearic acid, as disclosed in U.S. Pat. No. 4,224,212, or it may be derived from two or more different hydroxy carboxylic acids. GB 1 373 660 discloses polyester amine dispersants obtainable by reaction of a polyester from hydroxycarboxylic acid with diamine, especially alkylene diamines and salts thereof.